Different computers can use different video graphics environments to display images on monitor screens. For example, different environments can use a different number of bits to represent pixels. Differences in graphic environments can cause images developed in a first graphic environment to be altered when displayed in a second. For example, pixels in Internet images are often represented by eight-bit tuples offering millions of pixel colors, but are often displayed in a second environment offering a palette of only 256 pixel colors (e.g., a single 8-bit byte is used to represent pixel color). The second environment may dither the image to simulate colors provided by the first environment. One type of dithering intermixes differently colored pixels to produce an appearance of a color not found in a palette (e.g., intermixing red and blue pixels can produce the appearance of purple). While dithering can be effective, the technique often produces noisy, grainy images.
Some image developers solve this problem by limiting themselves to a small subset of the pixel colors (i.e., "Web-safe" palette colors) their environment provides. Others try to produce images that take advantage of the capabilities of more sophisticated environments while lessening the impact (e.g., dithering) of display in less sophisticated environments. Commonly, these developers produce an image in a first graphics environment, alter system parameters to replicate a different graphics environment (e.g., reduce the number of bits the system display uses to describe each pixel), reboot the computer, and view the image. To fix problems discovered by viewing the image in the second graphics environment, the developer can reset system parameters and reboot again.
Developers have also used Adobe Photoshop.TM. to view an image as it will appear in a different environment. Developers using Photoshop.TM. can save an image developed in a first graphics environment, maneuver through a series of menus to choose display options that replicate a second graphics environment, then open the saved image in the second environment. After noting image regions that appear unsatisfactorily, the developer can renavigate through menu selections to restore the original graphics environment and modify the original image. The developer can repeat this process until the image appears satisfactorily in both graphics environments.